Statement of the Technical Field
The inventive arrangements relate to RFID portal systems, and more particularly to RFID portals which identify a travel direction of RFID tags crossing a portal transition.
Description of the Related Art
The related art concerns RFID systems and more particularly RFID portals. An RFID portal is system which is used for tracking items passing through doorways, hallways or corridors. Conventional RFID portals identify the direction of RFID tags crossing a portal transition defined by a choke point through which items must pass when they move from one defined area to a second defined area. In many implementations, an RFID portal consists at minimum of two separate antennas and a RFID reader. The tag directionality is easily determined by the order of the reads. A tag read by a first antenna and then by the second antenna is likely moving from the first to second antenna. However, this implementation requires multiple read zones with separated mounting points and cannot be applied to all use cases.
RFID portals can also use beam steerable antennas to detect the presence of RFID tags in different locations as they move through a portal zone. In a conventional configuration, the minimum setup is one RFID reader and one beam steerable antenna. In such scenarios, the physical separation between multiple antennas is no longer needed to determine tag directionality.
A number of organizations have set standards for RFID tags. One type of RFID tag for which a standard has been established is known as an EPCglobal UHF Class 1 Generation 2 (hereinafter “EPC Gen2”) type tags. These tags have certain well known characteristics.